1. Field of the Invention
The present invention relates to a submount for arranging electronic elements on a substrate, and to an arrangement comprising such a submount arranged on a substrate. The present invention further relates to a method and a device for assembling at least one such submount and an electronic element.
2. Related Art
Many types of textiles are used in every day life. Simultaneously, the use of electronic equipment in daily life, such as display devices, mobile phones, media players, navigation equipment, and different kinds of sensors increases dramatically. When electronic equipment is integrated into textiles, new application fields appear, such as textile based display devices, clothes that can tell the present location and point out the direction to a desired location etc.
For ultimate textile integration of electronic elements, the interconnecting substrate, e.g. the driving circuitry, should be entirely made of fabrics.
However, direct attachment of distributed electronic components, such as LEDs, onto a textile substrate for example by using conductive epoxy is a very delicate and time-consuming process. Direct soldering of the components onto the textile substrate may often be problematic as well, for example due to the low melting temperature of several textile fibers, such as polyester.
Thus, there is a need in the art for means and methods for arranging electrical components on textile substrates that can be used independent on the nature of the textile fiber, which are well suited for automated arrangement, and which provides a robust attachment of the electronic components on the textile substrate.
WO 2010/086416 A1 (WO '416) discloses a stretchable electronic device comprising a stretchable interconnection electrically connecting two electronic components. The stretchable interconnection comprises an electrically conductive channel and a first flexible supporting layer provided for supporting the electrically conductive channel. The supporting layer has a predetermined second geometry that restricts stretchability of the electrically conductive channel below its elastic limit. (See Abstract)
WO '416 mentions on page 15, lines 20-22 the possible use of a submount (interposer), i.e. an intermediate component between the substrate and an electric component as follows: “These support parts create flexible circuit islands on which several electronic components or interposers 69, 79, 89 can be mounted.” WO '416 however discloses no details about the construction of a submount.
It is noted that DE 10 2007 014 477 (DE'477) discloses a method for fastening electrically conductive thread to textile fabric. Therein electrically conductive thread is used as reel thread and fastening is carried out in form of two-thread lock stitch seam. The electrically conductive thread may be used as needle thread, or may be inlaid in a zigzag seam as a third thread system. (Abstract) In an embodiment, as described in paragraph 50 with reference to FIG. 11, a Velcro-tape (Klettkontaktierung/klittenband contact) is used to mount a LED on the fabric.
A known construction of a submount for integrating electrical components into textiles is described in WO 2008007237 (A2). The submount disclosed therein comprises a head member and at least one substrate-engaging member protruding from the head member. The head member comprises at least two, from each other isolated, electrically conductive portions, where each electrically conductive portion comprises a component contact, adapted for connection of electronic components thereto, and a substrate contact arranged on said substrate side, adapted for bringing said electrically conductive portions in contact with a circuitry comprised in said substrate. The submount of the present invention may be used to attach electronic components, such as light-emitting diodes, to a textile substrate, without the need for soldering the electronic component directly on the substrate.
In an embodiment, the head member of the submount represents a male member of a snap fastener. This submount is especially adapted for being connected to an electronic component having the shape of representing a female member of a snap fastener. The head member comprises an engaging protrusion for engaging with a recess in the electronic component.
The first component contact of the head member is arranged on the base surface of the head member. The second component contact of the head member is arranged at the top of the protrusion. For connection to this, the electronic component has a first connector arranged on the base surface, and a second connector arranged in the engaging recess. Thus, when the electronic component is snap-locked on the submount, the first component contact, arranged on the base surface of the head member is contacted to the first connector, arranged on the base surface of the electronic device. Further, the second component contact, arranged on the engaging protrusion, is contacted with the second connector arranged in the engaging recess of the electronic component.
In the known arrangement it is required that the electronic component has a relatively high mechanical strength, so that it is not damaged when it is snapped onto the submount.
An improved type of submount is desired that is also suitable for mounting more fragile electronic components.